I've done some light schematic building lately, and this mod is by far the easiest and most effective method I've found. It's simple and convenient to use, completely mod/game agnostic (a must for development outside of MTG), and offers reasonably polished presentation.
The only features that feel like they're missing is an option to load schematics registered by mods and a quick way to swap or flood-fill nodes in a schematic, but these are easy to work around or provide externally anyway. Overall, this mod makes for an incredibly useful development tool.
This is the mod that made schematics accessable to me. The system is simple, and wonderfully free from dependencies. For modders and anyone who needs to create or view schematics this is the best option I've found.